Review on Vertisol Management for the Improvement of Crop Productivity in Ethiopia

Vertisols (deep black clay soils, often known as "black cotton soils") cover 8 million ha of the Ethiopian highlands. They account for about 70 percent of all highland soils with slopes between 0 and 8 percent. The high clay content of the Vertisols is responsible for their heavy water logging in highland areas with abundant rainfall and relatively low evaporation rates. This imposes severe restrictions on the traditional agricultural use of these soils and only 25 percent are currently cropped, mainly using residual moisture. Much of this land is left fallow and subject to erosion during the heavy rains. Evidence suggests there would be substantial increases in crop yields on Vertisols if excess surface soil water were drained off and if appropriate cropping practices were used. A research and outreach project on the improved management and utilization of highland Vertisols is examining the use of animal- powered devices for surface soil drainage, planting and tillage, the development of new cropping systems on drained Vertisols, and improved management of plant nutrients with the use of low cost phosphates and legumes as sources of nitrogen.The current BBM is found to be a good example of appropriate and sustainable technology that meets the needs of smallholder agriculture. It is very simple and low-cost technology and its application does not require farmers to have or develop advanced skills. However, combining the BBM technology with other complementary technologies like improved high yielding rust resistant wheat varieties and fertilizers is very important in increasing the impacts of BBM adoption. Keywords: clay content, cropping practices, improved management, Vertisol managemen